Wednesday, July 20, 2011

Odd Ubuntu Problem

We had a pretty serious power failure a few days ago--and afterwards, my dual boot Linux/Windows box became a zero boot box.  The hard disk passes the BIOS diagnostics, but it comes up in grub (which means that it must be booting something from the hard disk).  I can see three partitions at the grub prompt: (hd0), (hd0,5), and (hd0,1).  The (hd0,5) is the Windows partition, and (hd0,1) is the Ubuntu 9.0 Linux partition.  I can't seem to get either of them to boot.  (Admittedly, the sparse help display of grub might be part of the problem on this.

I downloaded and burned an Ubuntu 11.04 boot CD, and thought, "What the heck, I will get the latest version of Ubuntu Linxu while I am at it."  But it won't boot from the CD.  Or rather, it starts to bring up the Ubuntu logo, and then:

(initramfs) mount: mounting /dev/loop0 on //filesystem.squashfs failed: Input/output error
Can not mount /dev/loop0 (cd/romcasper/filesystem.squashfs) on //filesystem.squashfs

Any suggestions?  If I spend enough time hunting, I can probably find what I need to reinstall whatever goes in some boot file to tell it to boot from my Linux partition--but I know that there are some Linux fans here, and one of you probably knows the answer.


  1. Sounds like you could have a hardware problem. Boot from your Ubuntu boot CD and choose the memory test option from the start-up menu, then let it run overnight. If it comes back with zero errors, great; if not, you might need to replace some hardware. Whether the hardware you'll need to replace is the power supply, RAM, or motherboard... would have to wait on further testing to determine; all the memory test will tell you is that sometimes, the values written to RAM aren't the same values that the system immediately reads from RAM. Which will cause any operating system to crash.

    Oh, and before you do that, try that same Ubuntu boot CD in another computer, just to eliminate the possibility that you happened to burn a bad copy.

  2. What he said. "Input/output error" typically indicates one piece of hardware is not responding as expected. Could be and of RAM, disk drive, mainboard. The fact that these new problems coincide with a serious power failure make it seem even more likely yo me.

  3. The disk drive is almost new--I installed it in the last two or three months. (Hopefully still in warranty.) It turns out that all of my computers are plugged into UPSs, so there should be pretty decent isolation from power surges--certainly better than the average power strip.

  4. That reeks of hardware issues to me, too. Possibly the motherboard.

    (As a lark, open it up and wiggle the connectors, unplug and replug 'em.

    Can't hurt, and I've seen stranger random problems that were correlated-but-not-caused by "the obvious cause" like a power outage.)

  5. Try SinRite ar
    leo Laporte recommends this. Does Security Now podcast with owner Steve Gibson.
    may recover fix problem

  6. If you have the install dvd you used previously I'd try that first. If that won't boot then hardware is likely at fault.

    Also, in grub you should be able to browse the partitions using tab completion and the cat command. eg.

    cat (hd0,0)/ will show a file listing for the partition if grub can read it.